This program project has as its goal the achievement of a detailed elucidation of molecular mechanisms underlying hormonal control of the reproductive tract. Central to our view of these mechanisms is the concept that hormones interact specifically with protein receptors and that this interaction has a causal relationship in the mechanism of hormone action. The program project, consisting of seven core units and research projects, is an integrated research effort directed toward achieving the stated goal. The component core facilities and research projects are: 1. Administrative core facility; 2. Combined central radioimmunoassay laboratory and Bio-organic analysis-synthesis facility; 3. Regulation of protein synthesis in human placenta; 4. Estrogen and anti-estrogen binding and action; 5. Steroid effects on protein structure and hormone action; 6. Binding and biological activities of hCG. 7. Steroidogenesis in dispersed, superfused ovarian cells. BIBLIOGRAPHIC REFERENCES: F. Sweet: Reactivation of an affinity labeling steroid oxidoreductase. I. Inactivation of 20 Beta-bromoacetoxyprogesterone vs 6 Beta-bromoprogesterone. Steroids (In press 1/76). F. Sweet, and N.K. Adair: Synthesis of 21-aminoprogesterone bisketal. Steroids (In press 2/76).